code: def test_latitude_true_scale():
      lat_ts = 20.0
      crs = ccrs.Mercator(latitude_true_scale=lat_ts)
      other_args = {
          "ellps=WGS84",
          "lon_0=0.0",
          "x_0=0.0",
          "y_0=0.0",
          "units=m",
          f"lat_ts={lat_ts}",
      }
      check_proj_params("merc", crs, other_args)
  
      assert_almost_equal(
          crs.boundary.bounds,
          [-18836475, -14567718, 18836475, 17639917],
          decimal=0,
      )
  
file_path: cartopy/lib/cartopy/tests/crs/test_mercator.py
imports: from numpy.testing import assert_almost_equal
  import pytest
  import cartopy.crs
  from .helpers import check_proj_params
label_desc: Use image node_id 5 for calling a global function with example usage: test_latitude_true_scale() without return types